1.Barry Is Not Very Good at Getting His First Serve in When Playing Tennis. His Long-Term

Probability 3

1.Barry is not very good at getting his first serve in when playing tennis. His long-term average is one in ten. What is the probability that Barry’s next serve

(a)goes in(b)does not go in?

2.A number is chosen at random from the first 20 positive whole numbers. What is the probability that it is not a prime number?

3.A card is drawn at random from an ordinary pack of 52 playing cards. What is the probability that it is not a two?

4.One letter is chosen at random from the letters of the alphabet. What is the probability that it is not a vowel?

5.A box of 60 coloured crayons contains a mixture of colours, 10 of which are red. If one crayon is removed at random, what is the probability that it is not red?

6.A number is chosen at random from the first 10 whole numbers. What is the probability that it is not exactly divisible by 3?

7.One letter is chosen at random from the letters of the word ALPHABET. What is the probability that it is not a vowel?

8.In a raffle, 500 tickets are sold. If you buy 20 tickets, what is the probability that you will not win first prize?

9.If you throw an ordinary six-sided die, what is the probability that you will not get a score of 5 or more?

10.A card is drawn at random from an ordinary pack of playing cards. What is the probability that it is

(a)an ace(b)a spade

(c)not a club(d)not a seven or an eight?

11.A bag contains a set of snooker balls (i.e. 15 red and 1 each of the following colours: white, yellow, green, brown, blue, pink and black). What us the probability that one ball removed at random is

(a)red(b)not red

(c)black(d)not red nor white?

12.There are 60 cars in the station car park. Of the cars, 22 were made in Britain, 24 were made in Japan and the rest were made in Europe but not in Britain. What is the probability that the first car to leave was made in

(a)Japan(b)not Britain

(c)Europe but not Britain(d)America?

13.One number is chosen at random from the whole numbers 1 to 100 inclusive. What is the probability that the number

(a)is not a multiple of ten

(b)is not prime

(c)has two digits?

14.A train operator states that, over the last year, 3 out of every 10 trains that ran arrived early.

(a)Use this information to estimate the probability that, when you next travel on one of these trains, it will not arrive early.

(b)Jane said “This means that there is a 7 in 10 chance that the train will arrive late.” Is she right? Give reasons for your answer.

(c)Say why the answer to part (a) can only be an estimate.